Notation of the Phone Numbers
This page describes how telephone numbers must be written in accordance with Recommendation E.164 and dialed for calls.
- Background information
- Writing phone numbers standard-compliant
- Dialing phone numbers standard-compliant
Background information
Phone numbers are often stored in personal address books or contact directories. Furthermore, they are presented on websites or integrated into the personal footer under emails.
By linking your address books to the telephone system via CTI, it is possible to make a call directly from your address books.
Only a standard compliant storage enables a guaranteed reachability of the destination number from all networks (RWTH telephone network, mobile network, international roaming or home network).
Writing phone numbers standard-compliant
Always write phone numbers in FQTN (Fully Qualified Telephone Number) according to the ITU-T standard E.164. This has the advantage that the number is always unique.
This means that the telephone number can be uniquely addressed by every telephone system and every telephone service provider.
Here you can find exampls of standard-compliant spelling:
Name | Phone number E.164 | alternative spelling | Speed dials (only within the RWTH) | WRONG spelling |
|---|---|---|---|---|
| IT-ServiceDesk, RWTH | +492418024680 | +49 241 80-24680 | 24680 0 80 24680 0 0241 80 24680 0 0049 241 80 24680 | +49 (0)241 80-24680 80-24680 |
Dialing phone numbers standard-compliant
If you call people via the Cisco telephone system, you must ensure that you dial the number correctly in addition to the spelling.
- For internal RWTH calls, it is sufficient to dial the last 5 digits of the phone number.
- (For example, for the phone number +492418012345 only 12345)
- For RWTH external numbers, dial a leading 0 (outside line access) and the respective area code if the number is outside Aachen and then the phone number.
- (For example 0 02405 12345)
- For RWTH international numbers, dial a leading 0 (outside line access), another 0 for international calls, then the country code (e.g. 031 for the Netherlands), the respective area code without a leading zero and then the number.
- (0 0031 1234 12345 or +31 1234 12345)
It is easiest to enter the full number directly (in the format +31123412345). This also applies to cell phone numbers and when setting up call forwarding!
